List of studies
It is important to recognize, that research -- both scientific and within NLP -- is susceptible to a variety of experimental errors. Readers should be aware of this if relying upon any given report, and confirm for themselves whether those concerned have taken adequate measures to control for known sources of error.
Generally supportive (adica studii care arata ca NLP are rezultate bune)
Allergy cure Swack (1992) trialled the NLP "10 minute allergy cure" on a small group of 10 individuals, both in isolation and with full NLP followup in the case of failure. The initial results were 70% (7) success with 30% (3) relapse over time; of the 3 however, 2 fully recovered when other NLP techniques such as Timeline and V/K dissociation were also allowed to be used.[1]
Allegies (athsma) Lund and Lund (1994) tested NLP on asthmatics, finding that whereas a control gropup deteriorated predictably, the NLP group gained a significant reversal of their deterioration, as measured by lung capacity. Unstable lung function measurements fell to under 10% in the NLP group, and sleep disorders and use of inhalers and acute medication both fell to zero in the NLP group. (reported at Danish Society of Allergology Conference 1994, and European Respiratory Society Conference 1994)[2]
Anchoring and state change Brandis (1986) found that success at self-anchoring, when utilized, was "strongly related" to changes in the individuals' parental anger responses[3]
Anxiety and one-session anchoring Reckert (1994) studied one-session anchoring as a way to treat test anxiety, with "positive results"[4]
Anxiety and control Konefal (1992) found that "[r]esults confirm the effectiveness of neurolinguistic programming in lowering trait anxiety and increasing the sense of internal control"[5]
Child development and home environment Miranda Paula & Palma (1999) examined in clinical trials whether NLP could help children and parents in shanty towns. They used an NLP intervention program over 15 sessions (approx 10 helped with NLP, 27 control), measuring children’s psychomotor development, home environment and maternal mental health before and after. They concluded "There was a trend that indicated positive effects on the home environment" (reported in Sao Paulo Medical Journal)[6]
Information gathering in the profoundly deaf Davis (1984) found that "[NLP]'s structure, terminology, and sound theoretical principles resulted in gathering valuable process information" when counselling prelingually deaf adults[7]
Lessons from 9/11 Acosta & Levenson (2002) reviewing the "lessons from ground zero" for emergency mental health and trauma response in the wake of 9/11, stated that "The suggested interventions are based on the theory and clinical practice of Emergency Medical Hypnosis, Neuro-Linguistic Programming, and Ericksonian Psychotherapy."[8]
Meta-model violations and dysfunctional families Macroy (1978) found that more dysfunctional families "substantially" correlated with meta-model violations, and concluded that "challenging metamodel patterns is an important way to enhance the ability to achieve satisfaction socially"[9]
Meta-programs and exam results Brown& Graff (2004) found "[s]ignificant correlations between meta programme patterns and the students’ assessment performance" and that specific NLP meta-programs identified tended to also correlate with good or poor performance in specific subjects.[10]
Milton model elicits ideomotor responses under general anaesthesia Cheek (1981) demonstrated that NLP Milton Model language use is capable of reaching and influencing the unconscious mind, by inducing 3000 patients to respond with formal yes/no hand signals to questions, whilst fully anaesthetized.[11]
Milton model and rapport Forster Jansen Margenrot Unterberger (1993) investigated the conditions which are decisive for rapport and concluded that the NLP Milton Model was "very helpful"[12]
Mirroring and empathy Sandhu Reeves Portes (1993) found that NLP mirroring, when done effectively, had "significant effect" on client measurement of empathy in a cross-cultural counselling scenario[13]
Modeling in education Trevor Day (2005, PhD project) states "Neuro-linguistic programming (NLP) is becoming increasingly influential in classroom practice (e.g. Ginnis, 2002)" and reports "early success using NLP modelling with sixth form students" (presented at British Educational Research Association (BERA) Annual Conference at the University of Glamorgan)[14]
NLP as a general client tool Weerth (1992) tested 29 people who were trained in general non-specific use of submodalities, finding that numerous direct effects were reported, spontaneous long term "emotion relevant" use was occurring, and that "successful uses of the trained methods could be assessed in around 66% of the participants" in everyday life. A six-month followup confirmed durability of changes.[15]
NLP-trained observers and eye movement existence and detection Buckner (1987) found that "coefficients of agreement (Cohen's K) between participants' self-reports and trained observers' records indicate support for the visual (K=.81, p<.001) and auditory (K=.65, p<.001) portions of the model", and that "interrater agreement (K=.82) supports the NLP claim that specific eye movement patterns exist and that trained observers can reliably identify them"[16]
NLP-trained observers and memory retention Janvier & Ghaoui (2004) noted that "The trained observer can consciously note these [body languages] and use the information gained to interact using Neuro-linguistic programming language" citing Craft, 2001; Janvier & Ghaoui, 2003b; Sadowski & Stanney, 1999; and Slater et al., 1994, and "[significant indication] that using [NLP] in Human-Computer Interaction does indeed improve memory retention by some 15% (p=.0001)"[17]
Predicate matching and empathy Asbell (1983) found that predicate matching was perceived as the "most helpful" of 4 strategies and gave higher ratings for counsellor empathy.[18]
Predicate matching and eye movements Baddeley (1991) found positive correlation between predicates and certain predicted eye movements[19]
Response prediction in virtual realities Steed, Slater and Usoh (undated) found that when working with virtual reality systems (eg architects walk-through), a traditional model of presence purely in terms of exogenous factors was unsuccessful, but "[a] tentative model based on the endogenous factors of the subject using Neuro-Linguistic Programming did however provide a good prediction of a person's reported sense of presence"[20]
Serious chronic conditions Unterberger Ulbrich (1998) found that when NLP was used to treat serious chronic conditions in clinical trials, comprising 12 hours over 3 weeks, they "prove to be quite successful procedures" and "significant results show up", noting that "the participators in the training judge the success of their rehabilitation measures throughout more positively than the members of the control's group".[21]
Severe DSM conditions Genser-Medlitsch & Schütz (1997) tested the effects of NLP master practitioners working on 55 clients with severe DSM conditions (schizo-affective, psychosis, psychosomatic, depression, dependency, etc), many on psychiatric drugs. The control group of 60 had milder symptoms. After treatment of the NLP group, 2% felt no different, 98% felt better or much better, none felt worse (control group: 48% no different, 36% better, 15% worse). After therapy, the clients who received NLP scored higher in their perception of themselves as in control of their lives (with a difference at 10% significance level), reduced their use of drugs, used more successful coping methods, and reduced symptoms such as anxiety, aggression, paranoid thinking, social insecurity, compulsive behaviours, and depression. Positive changes in 25 of 33 symptom areas (76%) occurred as a result of NLP, positive changes in 3 areas occurred in both NLP and control groups. The researchers concluded "It could be established that, in principle, NLP is effective in accordance with the therapeutic objective." (Genser-Medlitsch & Schütz, 1997, Does Neuro-Linguistic psychotherapy have effect?)[22]
Social work Frank (1997, Germany) investigated NLP in social work, finding "enormous changes" and that "very many of the people indicated that they could increase their adaptability, feel technically more competent and make a more intensive self reflection", summarizing that it had "fallen out very positively"[23]
Spelling strategies Loiselle (1985, University of Moncton, New Brunswick) tested various spelling strategies and found: control=no change, "visualize"=10% better, "visualize up/right" (ie NLP Visual) = 20-25% better, "visualize down/left" (ie NLP Kinesthetic)=15% worse.[24]
Spelling strategies Almost identical results were obtained by Malloy (1989) - the NLP spelling strategy produced a 25% improvement in spelling ability (and 100% retention) compared to no change in a control group but that spellers told to visualize in what NLP claims is a Kinesthetic manner (down/left) were scored around 10% worse.[25] Swish and nailbiting Wilhelm (1991, Germany) tested the "swish" pattern for nail-biting, finding "significant variations of the nailbiting" and that results were stable up until followup[26]
Trance depth and sensory system matching Yappo (1981) found that when subjects were put in trance using a variety of inductions in different sensory systems, and EMG (electromyograph) and self-assessment were used to measure effects of predicate matching, both measures showed that deeper trance was induced when the preferred sensory system was used[27] V/K (phobia) Einspruch (1988) found "marked improvement" over an 8 week period in a test of 31 patients who undertook NLP phobia treatment[28]
V/K (rape trauma) Koziey and McLeod (1987) found that the NLP V/K technique produced a "positive reduction in anxiety in teenage rape [trauma]"[29]
V/K (DSM criteria trauma) Muss (1991) examined the impact of NLP V/K technique on 19 insurer-referred police officers who met DSM-III post-traumatic stress disorder criteria, following up at 3-24 months. Most stated it had greatly helped, in long term followup 100% of those reached confirmed freedom from recurrance.[30]
V/K (trauma) Dietrich (2000, "traumatology") reviewed NLP V/K dissociation trials, and concluded that NLP was "promising" and that "intrusive symptoms, avoidance behaviors, and interpersonal and occupational functioning improved for many of the participants in the studies reviewed"[31]
Generally dismissive (adica studii care arata ca NLP are rezultate proaste sau nu are rezultate)
Mixed or indeterminate findings
Predicate matching Heap (1988) found that findings were "on the whole" negative, but also that "a number of positive outcomes" were reported. He interprets this to mean that there was an effect but it was perhaps more general than expected, noting that this would agree with expectations of NLP writers and also other findings that "with increasing familiarity, client and counsellor tend to converge in their usage of certain linguistic structure".[32]
Weight loss Bott (1995) found that NLP gave "partially positive effects" for treating psychogenic weight loss. Unclear if there was a control group.[33]
Management learning Dowlen (1996) performed own research and also reviewed the existing research, to examine whether NLP was "help or hype" in management training. He concluded that: "NLP techniques using language patterns and questioning techniques appear to be of use... existing research evidence is limited and inconclusive... NLP is enthusiastically supported by those who practise it, and that is both its strength and potential weakness."[34]
Meta-studies and similar commentaries on research
Sharpley (1984) performed a metastudy of 15 studies seeking to test for a 'preferred representation system.' He concluded strongly that there was "little supportive evidence and a large amount of data opposing the validity of the concept." The concept of a PRS was (whether earlier or later than this) dropped within NLP.
Einspruch & Forman (1985), responding to Sharpley, criticized all 39 studies to that date (including all 15 of Sharpleys') for serious errors, and concluded that as a result it was "not possible at this time to determine the validity of either NLP concepts or whether NLP-based therapeutic procedures are effective": [35]
"There is a growing body of empirical literature on Neuro-linguistic programming (NLP). A review of this literature by Sharpley (1984) failed to consider a number of methodological errors. In the present article the authors identify six categories of design and methodological errors contained in [empirical studies] through April 1984. These categories include (a) lack of understanding of the concepts of pattern recognition and inadequate control of context; (b) unfamiliarity with NLP as an approach to therapy; © lack of familiarity with the NLP "Meta-Model" of linguistic communication; (d) failure to consider the role of stimulus-response associations; (e) inadequate interviewer training and definitions of rapport; and, (f) logical mistakes. ... Suggestions are offered for improving the quality of research on NLP."
Some of these criticisms were later challenged or rebutted by Sharpley, but the majority of them are, in general, accepted. Sharpley published a follow-up review (1987):[36] "There are conclusive data from the research on NLP, and the conclusion is that the principles and procedures suggested by NLP have failed to be supported by those data. Perhaps NLP principles are not amenable to research evaluation. This does not necessarily reduce NLP to worthlessness for counseling practice. Rather, it puts NLP in the same category as psychoanalysis, that is, with principles not easily demonstrated in laboratory settings but, nevertheless, strongly supported by clinicians in the field." [37]
Heap says of his own research into matching predicates (1988) that: "Einsprech and Forman are probably correct in insisting that the effectiveness of NLP therapy undertaken in authentic clinical contexts of trained practitioners has not yet been properly investigated." [6]
Druckman (1988) reports that anecdotal evidence on NLP is broadly credible and positive, but that most attempted studies are heavily flawed, such as (a) equating subjective empathy with clinical effectiveness, (b) studying NLP as a theory, rather than as an influencing technique pitted against existing influencing techniques, © Attempting to replicate findings of NLP using subjects, observers, or experimental designers who lack NLP training, and (d) lack of studies on NLP as a trainer modeling system. He concludes that as a result of the study flaws, and despite the anecdotal support:[38] "Ignoring where the burden of proof lies, the fact remains that the experimental evidence fails to provide support for NLP... Overall, there is little or no empirical evidence to date to support either NLP assumptions or NLP effectiveness."
Platt (2001) observed that whilst studies evaluating specific NLP points such as predicates, representation systems and eye movements tended to give positive results only around 15-35% of the time, when he examined studies of the effects of NLP applied in its complete context, in this case phobia cures, "56% found positive evidence to support NLP's effectiveness."
Findings within neuroscience and cognitive science NLP and neurotransmitter/neurological activity Baxter (1994) found that NLP reframing used to treat obsessive compulsive disorder in place of Prozac resulted in the same raised serotonin levels and reduced caudate nucleus activity as control subjects who took medication (as measured by Positron Emission Tomography scans of the brain)[39]
Submodalities and sensory perception Visual submodalities have been shown to affect kinesthetic states, for example room color has an effect on temperature perception (Berry, Journal of Applied Psychology 45/4) and packaging color changes the effectiveness of the placebo effect (Buckalew and Ross, 1981)[40] |